Momentum and heat transfer across the foam-covered air-sea interface in hurricanes

Procedures of formal averaging over the air-sea interface are applied to both momentum and enthalpy surface-transfer coefficients, C_D and C_K, in hurricane conditions. The transfer coefficients across the total area of the sea surface and water-covered portions of the sea surface, C_D, C_K, and C_Dw, C_Kw, are estimated by measurements in the open-sea and laboratory (foam-free) conditions, respectively, while the transfer coefficients across the foam-covered portion of the sea surface, C_{Df, Kf}, which cannot be measured directly, are estimated using the splitting relations. Applying the Monin-Obukhov similarity theory at the neutral stability atmospheric conditions to the transfer coefficients (separately for the foam-free, foam-covered, and total sea surfaces) yields the roughness lengths Z_Dw, Z_Kw, Z_Df, Z_Kf, and Z_D, Z_K. The study is aimed at the description of an anomalous, as compared with laboratory conditions, behavior of the momentum and enthalpy transfer coefficients in hurricane conditions with wind speed U₁₀ by the effect of the foam slipping layer sandwiched between the atmosphere and the ocean.